Schlumberger

Digital Group Forming (DGF)

Customized noise attenuation using single-sensor data

In the pursuit of improved signal-to-noise ratio, conventional acquisition systems rely on summing the responses from a large numbers of individual detectors before digitizing and recording. The response from such arrays is rarely optimal across a survey area, or from one prospect to the next. Noise attenuation is compromised and high signal frequencies are attenuated. The result can be masked structural features and poor resolution images.

The single-sensor principle of Q-Technology allows for individual detectors to be digitized and recorded separately. This enables noise attenuation filters to be optimally designed for each dataset, and applied before group forming - Digital Group Forming (DGF).

Due to the ultra-fine detector spacing, low frequency, low-velocity noise modes (e.g., streamer noise) can be attenuated without the effects of aliasing, and without the need to apply low-cut filters. Lacona is one example of a noise attenuation process designed specifically to be used pre-group forming.

In areas where detectors cannot be spaced on a regular grid (for example in built-up zones over producing oil fields) Geometry Compensating DGF can be applied to maintain noise attenuation performance. In addition, applying intra-array statics enables the individual detectors to be group formed while preserving much higher frequencies than conventional systems allow.

DGF improves the signal-to-noise ratio and broadens the recorded seismic data spectrum. This can result in a clearer image with higher structural resolution and greater confidence in the data taken forward into subsequent reservoir characterization processes.

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WesternGeco

Greater Data Confidence with Digital Group Forming

Improved resolution and image quality using Q-Technology.
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